U.S. patent number 5,323,767 [Application Number 07/970,969] was granted by the patent office on 1994-06-28 for portable arthroscope with periscope optics.
This patent grant is currently assigned to Citation Medical Corporation. Invention is credited to Daniel Kline, Michael Lafferty, Charles S. Slemon.
United States Patent |
5,323,767 |
Lafferty , et al. |
* June 28, 1994 |
Portable arthroscope with periscope optics
Abstract
A disposable arthroscope for examining the interior of a joint
and for carrying out diagnostic and therapeutic procedures within
the joint includes an elongated needle and a cap housing which has
a base plate. The proximal end of the needle is mounted on the cap
opposite the base plate, and the distal end of the needle extends
outwardly from the cap. The needle is a hollow tube which surrounds
an image guide and a bundle of illuminating fibers that extend
through the tube. A lens is attached to the distal end of the image
guide and is slightly angled relative to the longitudinal axis of
the needle. The proximal ends of both the image guide and the
bundle of illuminating fibers extend from the proximal end of the
tube and through the cap for exposure at the surface of the base
plate. The base plate of the disposable arthroscope is engageable
with a camera and with a light source to position the camera in
light communication with the image guide, and to position the light
source in light communication with the bundle. With these
engagements, the combination of disposable arthroscope, light
source and camera generate a visual display of an object that is
illuminated by the light source through the bundle of illuminating
fibers.
Inventors: |
Lafferty; Michael (Leucadia,
CA), Kline; Daniel (Carlsbad, CA), Slemon; Charles S.
(Encinitas, CA) |
Assignee: |
Citation Medical Corporation
(Reno, NV)
|
[*] Notice: |
The portion of the term of this patent
subsequent to February 23, 2010 has been disclaimed. |
Family
ID: |
27417837 |
Appl.
No.: |
07/970,969 |
Filed: |
November 3, 1992 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
814418 |
Dec 24, 1991 |
|
|
|
|
650066 |
Feb 4, 1991 |
5188093 |
|
|
|
Current U.S.
Class: |
600/109 |
Current CPC
Class: |
A61B
1/00096 (20130101); A61B 1/00165 (20130101); A61B
1/00179 (20130101); A61B 1/00183 (20130101); A61B
46/10 (20160201); A61B 1/042 (20130101); A61B
1/055 (20130101); A61B 1/0623 (20130101); A61B
1/317 (20130101); A61B 1/00188 (20130101) |
Current International
Class: |
A61B
19/00 (20060101); A61B 19/08 (20060101); A61B
1/055 (20060101); A61B 1/04 (20060101); A61B
1/313 (20060101); A61B 1/317 (20060101); A61B
1/00 (20060101); A61B 001/06 () |
Field of
Search: |
;128/4,6 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Olinger, C. et al., "Eighteen-Gauge Microscopic-Telescopic Needle
Endoscope with Electrode Channel: Potential Clinical and Research
Application", Surgical Neurology, May 1974 pp. 151-159..
|
Primary Examiner: Marone; Gene
Assistant Examiner: Lucchesi; Nicholas D.
Attorney, Agent or Firm: Nydegger & Associates
Parent Case Text
This is a continuation of co-pending application Ser. No.
07/814,418, filed on Dec. 24, 1991 and now abandoned, which is a
continuation-in-part of prior co-pending application for "Portable
Arthroscope with Periscope Optics, " Ser. No. 07/650,066 filed Feb.
4, 1991, now U.S. Pat. No. 5,188,093.
Claims
We claim:
1. A disposable optical device engageable with a camera assembly
for examining an internal structure of a body, which comprises:
a fiber optic image guide having a distal end and a proximal end,
said image guide defining a first axis;
an illuminating means joined with said image guide to establish a
needle therewith for insertion into the body;
a lens attached to said distal end of said image guide for
gathering light from said illuminating means, said leans defining
an optical axis oriented at an oblique angle relative to said first
axis; and
means for engaging said arthroscope with said camera assembly to
position said camera assembly in light communication with said
proximal end of said image guide for generating a visual display
signal of the internal structure of the body illuminated by said
illuminating means.
2. A device for examining an internal structure of a body as
recited in claim 1, wherein said needle further comprises a hollow
tube surrounding said image guide and said illuminating means for
supporting said image guide and said illuminating means.
3. A device for examining an internal structure of a body as
recited in claim 2, wherein said needle further comprises a hollow
tubular cannula having a lumen, said needle being positioned in
said lumen coaxially with said cannula to establish an annular
fluid passageway between said needle and said cannula, and said
arthroscope further comprises a source of liquid attached in fluid
communication with said passageway for bathing said internal
structure of said body with said liquid.
4. A device for examining an internal structure of a body as
recited in claim 2, wherein said camera assembly has a distal end
and said arthroscope further comprises a light focussing means
positioned in said camera assembly and a disposable scope assembly
removably attached to said distal end of said camera assembly for
supporting said needle and connecting said needle to said camera
assembly, said image guide extending through said scope assembly
and juxtaposed with said focussing means.
5. A device for examining an internal structure of a body as
recited in claim 4, further comprising a video device electrically
connected to said camera head for generating a video display
representative of said video signal.
6. A device for examining an internal structure of a body as
recited in claim 5, wherein said lens is a gradient refractive
index (GRIN) lens, said image guide is an optical fiber, and said
guiding means includes a plurality of optical illuminating fibers
in light communication with a quartz halogen lamp.
7. A device for examining an internal structure of a body as
recited in claim 6, wherein said light focussing means is axially
movable within said camera assembly for focussing light from said
image guide.
8. A device for examining an internal structure of a body as
recited in claim 7, further comprising a cannula assembly
surroundingly attached to said cannula and rotatably engaged with
said scope assembly.
Description
FIELD OF THE INVENTION
The present invention relates generally to medical diagnostic
devices. More particularly, the present invention relates to
arthroscopes. The present invention particularly, though not
exclusively, relates to hand-held portable arthroscopes for viewing
a relatively large area within a body joint.
BACKGROUND OF THE INVENTION
In the area of medicine, modern surgical techniques have been
developed for diagnosing and correcting damage to the interior
structure of body parts, e.g., bone joints. One of these modern
surgical techniques is arthroscopy, which can be used for examining
the interior structure of a body joint, for example, a knee, in
order to determine the extent of any damage to the joint. In other
words, arthroscopy permits viewing the internal structure of a body
joint without requiring conventional surgery on the joint. If
required, relatively non-invasive corrective surgery can be
performed in conjunction with arthroscopic examination techniques
to repair joint damage which is discovered during the
examination.
Arthroscopic examination typically involves inserting a probe into
the joint to be examined. The probe has an imaging device attached
to it, and the imaging device is in turn connected through the
probe to a video display for generating a picture of the interior
structure of the joint. Consequently, the operator of the
arthroscope is able to view, real-time, the interior structure of
the joint as the probe is inserted into the joint. By viewing the
internal structure of the joint, a diagnosis of any damage to the
joint can be made and appropriate treatment prescribed.
It is the case that existing arthroscopes require support equipment
which is relatively large and bulky and which is typically
permanently installed for use in an operating room. Consequently,
these arthroscopes cannot be easily moved from one location to
another, as may occasionally be required in a medical
establishment. Furthermore, arthroscopes which require sizable
support equipment are ordinarily expensive devices, and their
relatively high cost can make arthroscopic examination cost
prohibitive for some patients The present invention recognizes that
an arthroscope need not require large and expensive support
equipment and that there is a need to provide an arthroscope which
can be used in a Doctor's office for diagnosis of a joint injury.
Further, there is a recognized need to provide an arthroscope with
a sufficiently small disposable probe so that only a local
anesthetic is necessary.
Additionally, the probes of existing arthroscopes are typically
reusable devices and must accordingly be sterilized before each
use, in order to eliminate the possibility of infecting the
arthroscopy patient with a contaminated probe. Unfortunately, the
possibility remains that a reusable probe may not be effectively
sterilized and can accordingly remain septic, or that a properly
sterilized probe could become septic in the time period between
sterilization and use of the probe. The present invention
recognizes that an arthroscope can be provided which uses a
non-reusable probe to substantially reduce the likelihood of
transmitting infections.
In addition to the above considerations, it is also desirable for
the arthroscope to have a relatively wide field of view when the
probe of the arthroscope is positioned within the joint. This is in
order to maximize the size of the internal body area which the
arthroscope operator can examine. Providing a wide field of view
simply by enlarging the lens of the arthroscope, however, would be
counterproductive since the introduction of a larger lens would
require a larger entry site into the knee. A larger entry site,
however, is to be avoided. Accordingly, it is desirable that the
arthroscope be capable of viewing a relatively large area within a
joint, without requiring the use of a comparatively large
arthroscope lens.
It is accordingly an object of the present invention to provide an
arthroscope which is portable and hand-held. It is a further object
of the present invention to provide an arthroscope which has a
disposable probe that is insertable into a body joint for
generating a real-time picture of the joint. It is also an object
of the present invention to provide an arthroscope which can view a
relatively large portion of the internal structure of a joint.
Finally, it is an object of the present invention to provide an
arthroscope which is relatively inexpensive to manufacture and
comparatively easy and cost-effective to use.
SUMMARY
A portable diagnostic arthroscope has a hand-held generally
cylindrical hollow camera assembly and a disposable scope assembly
removably attached to the distal end of the camera assembly. The
disposable scope assembly can be rotated relative to the camera
assembly. Further, an elongated probe is rotatably attached to the
disposable scope assembly.
More specifically, the probe includes a hollow tubular steel
cannula which is mounted on a base assembly. The cannula extends
beyond the distal end of the base assembly, and the base assembly
is rotatably engaged with the scope assembly, so that the base
assembly, with its cannula, can be rotated relative to the scope
assembly. The cannula itself has an open distal end and an open
proximal end, so fluid can be introduced into the base assembly and
directed through the cannula to bathe the internal joint
structure.
In accordance with the present invention, a cylindrically-shaped
GRIN rod is attached to the end of a scope needle which is slidably
introduced through the cannula to position the GRIN rod inside the
cannula near the cannula's open distal end. Light which is
reflected by the interior structure of the joint enters the distal
base of the cylindrically-shaped GRIN rod and is focussed by the
GRIN rod onto the GRIN rod's proximal base.
To transfer the light back through the scope needle, the proximal
base of the GRIN rod is attached to the distal end of a fiber optic
image guide. This image guide extends through the scope needle
which is part of the scope assembly. Light which enters the distal
base of the GRIN rod is focussed by the GRIN rod onto the image
guide. Importantly, the image guide is bent near its distal portion
to form an angle of about twenty-five (25) degrees between the
distal portion of the image guide and the axis of the probe.
Consequently, the axis of the GRIN rod, which is attached to the
distal end of the image guide, is not parallel to the axis of the
probe. Accordingly, when the scope assembly is turned to rotate the
image guide about its axis, the distal base of the GRIN rod is
moved through a donut-shaped swath which enables the GRIN rod to
scan a relatively large area of the internal structure of the
joint.
The image guide is optically joined to focussing optics which are
mounted in the camera assembly. These focussing optics are axially
movable within the housing for focussing the image from the image
guide onto the camera head in the camera assembly. Thus, the
focussing optics are optically joined with a camera head which is
mounted in the camera assembly and which is electrically connected
to a camera control unit external to the arthroscope. As envisioned
by the present invention, the camera control unit can control a CRT
or other visual display device to display the image of the internal
structure of the joint.
Also, to illuminate the interior structure of the joint, a
plurality of optical illumination fibers are mounted within the
scope needle next to the image guide. These illumination fibers
extend through the scope assembly and are joined with a first end
of an optical cable that is mounted inside the camera assembly. In
accordance with the present invention, the second end of the
optical cable can be irradiated with light from a quartz halogen
lamp or other suitable light source which can be located either in
the scope assembly or the camera assembly, or located externally to
the camera assembly. Thus, light from the lamp can be transmitted
through the optical cable and illumination fibers to illuminate the
internal structure of the joint.
The novel features of this invention, as well as the invention
itself, both as to its structure and its operation, will be best
understood from the accompanying drawings, taken in conjunction
with the accompanying description, in which similar reference
characters refer to similar parts, and in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the novel portable arthroscope of
the present invention, seen in its intended environment;
FIG. 2 is a partial cross-sectional view of the novel portable
arthroscope of the present invention, as seen along the line 2--2
in FIG. 1;
FIG. 3 is an enlarged cross-sectional view of the distal end of the
probe of the novel portable arthroscope of the present invention
shown in FIG. 2; as seen along the line 3--3 in FIG. 2;
FIG. 4 is a partial cross-sectional view of an alternate embodiment
of the present arthroscope, as would be seen along the line 2--2 in
FIG. 1;
FIG. 5 is an enlarged cross-sectional view of the distal end of the
probe of the arthroscope shown in FIG. 4, as seen along the line
5--5 in FIG. 4;
FIG. 6 is an end view of the probe of the present invention;
FIG. 7 is a schematic view of the viewing area of the GRIN rod of
the present invention; and
FIG. 8 is a schematic view of the viewing area of the GRIN rod of
the present invention, as seen in the direction of arrow 8 in FIG.
7;
FIG. 9A is a perspective view of the disposable arthroscope of the
present invention; and
FIG. 9B is a cross-sectional view of the disposable arthroscope as
seen along the line B-B in FIG. 9A.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIG. 1, a portable hand-held arthroscope is
shown, generally designated 10. As shown, a portion of arthroscope
10 is inserted at an entry site 12 into a knee 14 of patient 16 to
examine the internal structure of the knee 14. Arthroscope 10 is in
light communication via optical illumination line 18 to a quartz
halogen lamp 20. While the present invention envisions use of a
lamp 20 which is a quartz halogen lamp for economy, it is to be
understood that lamp 20 may alternatively be any other suitable
type of light source well known in the art, e.g., metal halide.
FIG. 1 also shows that arthroscope 10 is electrically connected via
line 22 to a camera control unit 24. Camera control unit 24 can in
turn be electrically connected to a cathode ray tube (CRT) 26 and a
video camera recorder (VCR) 28, as shown in FIG. 1, for
respectively displaying and recording a video image of the internal
structure of knee 14.
Now referring to FIGS. 2 and 3, the details of arthroscope 10 can
be seen. As shown in FIG. 2, arthroscope 10 includes a probe 30
which is insertable into knee 14 (shown in FIG. 1). FIG. 3 shows
that probe 30 includes a scope needle 56 which has an optical fiber
image guide 32 which is coaxial with the scope needle 56 for most
of its length. FIG. 3 further shows that probe 30 includes a
plurality of optical illuminating fibers 34 which are positioned in
the scope needle 56 around image guide 32. Preferably, both image
guide 32 and illuminating fibers 34 are optical fibers which have
relatively large numerical apertures (NA). Additionally, although
there is no limitation on length, image guide 32 is preferably
short, i.e., the length of image guide 32 is preferably less than
about eight (8) inches.
As shown in FIG. 3, the distal segment 36 of image guide 32 is not
collinear with the proximal segment 38 of image guide 32. More
particularly, image guide 32 is bent so that the axis 40 of distal
segment 36 forms an angle 42 of about twenty five (25) degrees
relative to the axis 44 of proximal segment 38 and probe 30. Image
guide 32 is bent during the manufacturing process to the shape
substantially as shown in FIG. 3. For purposes of the present
invention, image guide 32 is of a type well known in the pertinent
art which comprises a single rod having a plurality of pixels (e.g.
10,000 pixels).
Still referring to FIG. 3, the proximal end 46 of a cylindrical
gradient refractive index (GRIN) lens 48 is bonded to the distal
end 50 of image guide 32. Preferably, GRIN lens 48 is the type of
internally-refractive lens made of thallium-doped glass
manufactured by Nippon Sheet Glass. In accordance with the present
invention, the length 52 of GRIN lens 48 establishes the focussing
characteristics of GRIN lens 48 as appropriate for the particular
application of arthroscope 10. Importantly, as shown in FIG. 3, the
distal end 54 of GRIN lens 48 defines a viewing window which is
offset, i.e., not perpendicular to, axis 44 of probe 30 as a
consequence of the bend formed in image guide 32 Stated
differently, the axis 40 of distal segment 36 (and, hence, the axis
of GRIN lens 48) is not parallel to the axis 44 of proximal segment
38 of image guide 32. Accordingly, when probe 30 (and, hence, image
guide 32) is rotated in a manner to be subsequently disclosed,
distal end 54 of GRIN lens 48 rotates through (and collects light
from) a relatively large area. Consequently, it may be appreciated
that by rotating probe 30, arthroscope 10 can examine a relatively
large area of the internal structure of knee 14 (shown in FIG.
1).
Continuing with the description of structure shown in FIG. 3, probe
30 is shown to include a hollow scope needle 56 which has a lumen
58. As shown, needle 56 is positioned in a surrounding relationship
with image guide 32 and illuminating fibers 34. Needle 56 is
preferably a hollow 16-gauge stainless steel tube, and image guide
32 and illuminating fibers 34 are positioned in the lumen 58 of
needle 56. The portion of lumen 58 which surrounds image guide 32
and illuminating fibers 34 is filled with an opaque epoxy material
60, to cushion and support image guide 32 and illuminating fibers
34 and to shield unwanted light from entering the image guide 32.
It is to be appreciated in reference to FIG. 3 that end 62 of epoxy
material 60 is preferably polished. As shown, distal end 54 of GRIN
lens 48 is recessed a distance d from end 62. In the preferred
embodiment, distance d is approximately five thousandths of an
inch. Additionally, FIG. 3 shows that the portions of lumen 58
which is proximal to GRIN lens 48 is left open and is not filled
with epoxy 60 in order to contain damage in the event probe 30
became inadvertently bent.
FIG. 3 further shows that probe 30 includes a 14-gauge hollow
stainless steel cannula 64 which is positioned in a surrounding
relationship to needle 56 with a passageway 66 between cannula 64
and needle 56 through which fluid can be infused. Though not shown
in FIG. 3, it is to be appreciated that GRIN lens 48 can be
protected from getting epoxy on the face of the GRIN lens 48 by
placing a polymide tubing around the GRIN lens 48. Further, this
polymide tubing will assist in protecting GRIN lens 48 from adverse
affects of thermal expansion.
Referring back to FIG. 2, cannula 64 of probe 30 is shown attached
to a disposable injection-molded hub 67 near proximal end 70 of
probe 30 to establish cannula assembly 68. Cannula assembly 68 is
formed with a chamber 72, and fluid can be pumped into chamber 72
through fluid port 74 from a fluid source (not shown). Fluid in
chamber 72 can enter open end 76 of cannula 64 and pass through
passageway 66. This fluid can subsequently be flushed out of open
end 78 (shown in FIG. 3) of cannula 64 to bathe the internal
structure of knee 14 to provide a clear viewing field when probe 30
is inserted into knee 14.
Cannula assembly 68 is rotationally engageable with a disposable
hollow injection-molded scope assembly 80, as shown in FIG. 2. More
specifically, bulb portion 82 of scope assembly 80 extends into
cannula assembly 68, and luer ears 84 of cannula assembly 66 can be
threadably engaged with luer fitting 86 of scope assembly 80. As
shown in FIG. 2, scope assembly 80 has a chamber 88 which is filled
with a resilient epoxy material 90. Epoxy material 90 is in turn
formed with key guides 92. Key guides 92 are configured for
engaging the keys 94 which protrude from a front tube 96. More
specifically, keys 94 of front tube 96 engage key guides 92 of
epoxy material 90 to establish a predetermined orientation of front
tube 96 relative to epoxy material 90. This predetermined
orientation ensures that the optical components in scope assembly
80 are properly aligned with associated optical components in front
tube 96 when scope assembly 80 is joined to front tube 96.
To hold scope assembly 80 against front tube 96, arthroscope 10
includes a retainer ring 98 which is slidably engaged with scope
assembly 80 and threadably engageable with front tube 96 to
removably connect scope assembly 80 to front tube 96. Furthermore,
as shown in FIG. 2, front tube 96 is rotatably positioned in a
camera assembly 100 and is held axially stationary with camera
assembly 100 by retaining screw 102. More particularly, retaining
screw 102 is threadably engaged with camera assembly 100 and
extends into a groove 104 which circumscribes front tube 96.
Consequently, front tube 96 can be rotated relative to housing
100.
In describing the optical path through arthroscope 10, reference is
made to FIG. 2, which shows that image guide 32 extends through
epoxy material 90 of scope assembly 80. As shown, end 106 of image
guide 32 is substantially coplanar with surface 108 of epoxy
material 90. In accordance with the present invention, surface 108
is polished to a smooth finish to establish an image plane 110.
Light from image guide 32 which passes through image plane 110
impinges upon a transparent sapphire window 112. It is to be
appreciated in reference to FIG. 2, that window 112 is fixedly
mounted on front tube 96. It is to be further appreciated that
window 112 is made of a material, i.e., sapphire, that is easy to
clean yet hard to scratch. Additionally, an optics base 114 is
slidingly positioned in front tube 96. Optics base 114 holds a
focussing optic 116 which is in light communication with sapphire
window 112. Thus, light which has passed through sapphire window
112 can enter focussing optic 116. Preferably, focussing optic 116
magnifies light from sapphire window 112 approximately seven times
(7.times.) and focuses the light onto a camera head 118 which is
also mounted in optics base 114. In the preferred embodiment,
camera head 118 is a charged coupled device (CCD).
In accordance with the present invention, camera head 118 converts
the light image from focussing optics 116 to an electrical signal
representative of the internal structure of knee 14. This
electrical signal is coupled into an appropriate electrical
connector 120. As disclosed above, the electrical signal is
conducted via line 22 to CCU 24 for further processing.
In describing the structure of arthroscope 10 which is used for
illuminating the interior of knee 14, reference is made to FIG. 2,
which shows that illuminating fibers 34 extend through epoxy
material 90 in a fiber bundle 122 to end 108 of epoxy material 90.
As shown, when the cap 80 is engaged with front tube 96, end 124 of
fiber bundle 122 is juxtaposed with an illumination GRIN rod 128
which is, in turn, connected to optical continuation fiber 130.
Continuation fiber 130 is in turn coupled to an optical connector
132, and optical connector 132 is in light communication with lamp
20 through optical line 18.
As disclosed above, arthroscope 10 incorporates a periscope feature
wherein scope assembly 80 can be rotated relative to camera
assembly 100 to rotate probe 30, and to selectively focus the image
present on image plane 110. More specifically, by rotating probe
30, distal base 54 of GRIN lens 48 rotates through a donut-shaped
swath for viewing a comparatively large area within knee 14. Also,
the present invention provides a capability for focussing the image
present on image plane 110 when scope assembly 80 is rotated
relative to camera assembly 100.
In describing the details of the structure of arthroscope 10 for
rotating probe 30 and for focussing the light image which is
present on image plane 110, reference is made to FIG. 2. Recall
that retainer ring 98 holds scope assembly 80 onto front tube 96,
and that front tube 96 can be rotated within camera assembly 100.
If desired, to limit the rotational motion of front tube 96
relative to camera assembly 100 to 170.degree. in both the
clockwise and counter-clockwise directions, stop screws (only stop
screw 136 shown in phantom in FIG. 2), can be threadably engaged
with front tube 96 to contact retaining screw 102.
In accordance with the present invention, a focussing ring 134 is
threadably engaged with front tube 96 and abuts optics base 114,
and a resilient annular 0-ring 138 is positioned between front tube
96 and optics base 114 to urge optics base 114 against focussing
ring 134. Focussing ring 134 can be operated to urge against optics
base 114 to move optics base 114 as appropriate for focussing the
image from image plane 110 onto the camera head CCD 118.
More particularly, as shown in FIG. 2, a button 140 is reciprocally
mounted in camera assembly 100. As shown, button 140 has a collar
142 which can abut camera assembly 100 to retain button 140 in
camera assembly 100. Furthermore, a flange 144 is fixedly attached
to camera assembly 100, and two biasing 0-rings 146 a,b are
positioned between flange 144 and collar 142 of button 140 to bias
collar 142 of button 140 against camera assembly 100 and provide a
water seal. When button 140 is depressed, end 148 of button 140
contacts focussing ring 134 to hold ring 134 stationary relative to
camera assembly 100. Thus, with button 140 depressed, when scope
assembly 80 (and, hence, front tube 96) is rotated relative to
camera assembly 100 scope assembly 80 is also rotated relative to
focussing ring 134, which is being held stationary relative to
camera assembly 100 by button 140. Consequently, stationary
focussing ring 134, which is threadably engaged with rotating front
tube 96, urges against optics base 114 to cause optics base 114 to
move axially relative to front tube 96, scope assembly 80, and
hence, image plane 110. When optics base 114 (and, hence, optic
116) is appropriately moved relative to image plane 110, the
optical image present on image plane 110 can be focused.
It will be appreciated in reference to the discussion above that
when scope assembly 80 is rotated clockwise relative to camera
assembly 100 and button 140 is depressed, ring 134 urges optics
base 114 distally relative to image plane 110 (i.e., toward the
right in FIG. 2). On the other hand, when scope assembly 80 is
rotated counterclockwise relative to camera assembly 100 and button
140 is depressed, resilient O-ring 138 urges optics base 114
proximally relative to image plane 110 (i.e., toward the left in
FIG. 2). Consequently, as optics base 114 is moved axially relative
to scope assembly 80, the focussing optics 116 which are mounted in
optics base 114 also move axially relative to scope assembly 80
(and, hence, image plane 110) to focus the image present on image
plane 110.
On the other hand, when scope assembly 80 (and, hence, front tube
96) is rotated relative to camera assembly 100, and button 140 is
not depressed, focussing ring 134 is not held stationary relative
to optics base 114. Consequently, optics base 114 is not moved
axially relative to image plane 110, and the focus of the image
from image plane 110 does not change. Importantly, however, image
guide 32 is rotated relative to camera assembly 100, so that the
area "viewed" by GRIN lens 48 rotates within knee 14 through a
relatively wide swath.
Finally, FIG. 2 shows that a screw 150 is threadably engaged with
front tube 96. Furthermore, screw 150 extends into a slot 152 that
is formed in focussing ring 134. It will be appreciated that the
widths of screw 150 and slot 152 establish the range of axial
travel of ring 134 relative to front tube 96. In the preferred
embodiment ring 134 can travel axially relative to front tube 96 a
distance of about twenty (20) thousandths of an inch.
Now referring to FIGS. 4 and 5, an alternate embodiment of the
novel arthroscope of the present invention is shown and generally
designated 200. It is to be understood that arthroscope 200 is in
all essential respects identical with arthroscope 10, with the
exceptions disclosed below. More particularly, arthroscope 200
includes a camera assembly 202, a scope assembly 204, and a cannula
assembly 206. As shown, scope assembly 204 is removably attached to
a front tube 208 by retainer ring 210, and front tube 208 is in
turn rotatably mounted in camera assembly 202.
FIG. 4 shows that cannula assembly 206 is rotatably attached to
scope assembly 204, and that cannula assembly 206 can be removed
from scope assembly 204. More specifically, cannula assembly 206
includes an abutment 212 and scope assembly 204 includes a detent
214 and a stop 216 which together establish an annular space 218.
As shown in reference to FIG. 4, cannula assembly 206 can be urged
proximally toward scope assembly 204 to snappingly engage abutment
212 with space 218 between detent 214 and stop 216. In accordance
with the present invention, when abutment 212 is engaged with space
218, cannula assembly 206 can be rotated relative to scope assembly
204. To disengage cannula assembly 206 and scope assembly 204, ends
220a, b of respective arms 222a, b of scope assembly 204 are urged
radially inwardly, and cannula assembly 206 is pulled distally away
from scope assembly 204.
As further shown in FIG. 4, cannula base assembly 206 includes a
reservoir 224 which is in fluid communication with the open
proximal end 226 of a cannula 228. As shown, a fluid line 230 can
be attached to cannula assembly 206 in fluid communication with
reservoir 224, for flushing fluid into proximal end 226 of cannula
228 and out of the distal end 232 of cannula 228 (shown in FIG. 5).
To prevent fluid from cannula 228 from spraying the operator of
arthroscope 200 when cannula assembly 206 is detached from scope
assembly 204, a pierceable fluid seal 234 can be positioned in
reservoir 224 substantially as shown. Scope needle 56, when
inserted into cannula 228, will pierce through the fluid seal 234.
Also, a retainer ring 238 is bonded to cannula assembly 206 to
retain fluid seal 234 within reservoir 224. Furthermore, an annular
o-ring 237 is positioned in groove 239 of cannula assembly 206 to
provide an additional seal between reservoir 224 and the operator
of arthroscope 10.
Still referring to FIG. 4, arthroscope 200 is shown to include a
plurality of optical illumination fibers which are grouped in a
fiber bundle 240. As shown, fiber bundle 240 extends through scope
assembly 204 and is optically joined to the distal base 242 of a
fiber optic taper 244. Taper 244 is shaped as a right circular
conical frustum, and the distal base 242 of taper 244 has
approximately half the area of the proximal base 246 of taper 244.
Proximal base 246 of taper 244 is joined to an optical transmission
fiber 248. It will be appreciated by the skilled artisan that taper
244 directs light from transmission fiber 248 into fiber bundle
240, to maximize the amount of light transmitted through fiber
bundle 240 for illuminating the internal structure of the knee.
Preferably, optical transmission fiber bundle 240 has a higher
numerical aperture than do the illumination fibers which constitute
fiber bundle 248. In any case, the numerical apertures for both
bundle 240 and 248 should be as high as possible. Additionally, as
shown in FIG. 4, transmission fiber 248 includes a slack loop
segment 250 to compensate for movement of transmission fiber bundle
248 when scope assembly 204 is rotated relative to camera assembly
202.
A second optical fiber taper 252 is shown in FIG. 4 for optically
connecting transmission fiber bundle 248 to a light source 254.
Taper 252 maximizes the light from light source 254 which can be
transmitted through transmission fiber 248.
Now referring to FIG. 5, the details of the distal end of
arthroscope 200 can be seen to include a probe, generally
designated 256. Probe 256 includes cannula 228. Additionally, probe
256 includes a steel needle 258, a plurality of optical
illumination fibers 260, and an optical fiber image guide 262. It
is to be understood that needle 258 and illumination fibers 260 are
substantially identical to the needle 56, fibers 34, and image
guide 32, respectively, disclosed for arthroscope 10.
As shown, image guide 262 substantially defines a longitudinal axis
264, and the distal segment 266 of image guide 262 is bent at an
angle 268 relative to image guide 262. Preferably, angle 268 is
about twenty five (25) degrees. FIG. 5 also shows that a
cylindrical GRIN rod 270 is attached to the distal end of image
guide 266. Consequently, the axis 272 of GRIN rod 270 is oriented
at an angle 268 to the axis 264 of image guide 262.
Referring briefly to FIG. 6, an iris 274 is shown at the distal
base of GRIN rod 270. Preferably, iris 274 is an opaque material
which is deposited onto GRIN rod 270. As shown in FIG. 6, iris 274
includes an aperture 276 through which light can pass. If desired,
the side surface 278 of GRIN rod 270 can also be coated with an
opaque material, to reduce the amount of stray light which can
enter GRIN rod 270 through surface 278 and thereby interfere with
image of the interior of the body surface under examination.
Referring back to FIG. 5, an epoxy material 280 is shown disposed
within needle 258 in a surrounding relationship to image guide 262
and illumination fibers 260. Distal surface 282 of epoxy material
280 is preferably polished, and, as shown in FIG. 5, distal surface
282 is contoured to optimize light transmission out of illumination
fibers 260 and into image guide 262. More specifically, portion 284
of surface 282 is substantially parallel to distal base 286 of GRIN
rod 270, to optimize light transmission into distal base 286. For
increasing the illumination of the interior body structure under
examination, portion 288 of surface 282 is oriented for maximizing
the refractive angle of light which exits illumination fiber 260b.
As shown, portion 288 of distal surface 282 of epoxy material 280
lies in a plane 290 that forms an angle 292 of about fifty degrees
with the axis 264 of image guide 262.
FIG. 4 also shows that a flexible protective sheath 300 can be
provided which maintains the sterility of the arthroscope 10 during
its use. Specifically, a raised ring 302 is formed on the retainer
ring 210 and a slip ring 304 is engaged with the raised ring 302.
The sheath 300, which is attached to slip ring 304 is then draped
over the camera assembly 202 and any other reusable components of
the arthroscope 10 which are likely to be septic. Accordingly, the
sterilized portions of arthroscope 10, which are also disposable
can be joined with the reusable camera assembly 202 which is
covered by the sheath 300.
Another specific embodiment for the disposable arthroscope of the
present invention is shown in FIGS. 9A and 9B and is generally
designated 400. For this embodiment, as with the other embodiments
for the arthroscope previously disclosed, the needle 56 is a hollow
tube which surrounds portions of both the image guide 32 and the
fiber bundle 122. As before, the fiber bundle 122 contains the
illuminating optical fibers.
The proximal end of needle 56 is mounted on a housing cap 401 and
the distal end of the elongated needle 56 extends outwardly from
the cap 401. As seen in both FIGS. 9A and 9B, arthroscope 400 also
includes a base plate 402 which is attached to cap 401 opposite
from where the needle 56 is joined to the cap 401. Further, base
plate 402 is formed with an aperture 404 which is centrally located
on the base plate 402, and with an aperture 406 which is distanced
from the aperture 404 and located near the periphery of base plate
402. It will also be seen in the Figures that the cap 401 is formed
with a pair of clips, 408 and 410, which are mounted on the cap 401
and which are diametrically opposed to each other relative to the
needle 56. As intended for the present invention, the clips 408 and
410 are used to engage the arthroscope 400 with the cannula
assembly 206.
The specific cooperation of structure for the arthroscope 400 will,
perhaps, be best seen in reference to FIG. 9B. There it is seen
that the image guide 32 extends through the needle 56 and through
the cap 401 for exposure through aperture 404 at the base plate
402. Also, it is seen that the fiber bundle 122 extends through the
needle 56 and through the cap 401 for exposure through aperture 406
at the base plate 402. As previously, disclosed the distal ends of
both the image guide 32 and fiber bundle 122 are attached to the
inside of the needle 56 at their respective distal ends. This
attachment, though sufficient to hold these components together,
does not extend through the length of the needle 56. Thus, the
image guide 32 and fiber bundle 122 are freely positioned within
the needle 56 through most of the length of the needle 56. This is
so in order to help compensate for differences in the thermal
expansion characteristics of the materials used in the manufacture
of arthroscope 400.
Another structural feature of the arthroscope 400 which helps
compensate for differences in thermal expansion characteristics, is
the interaction between the neck 414 of cap 401 and the grommet
416. As best seen in FIG. 9B, a grommet 416 which is made of a
relatively deformable material, such as an elastomeric material,
surround the proximal end of needle 56 and is positioned between
the needle 56 and the neck 414 portion of cap 401. The method for
attaching the grommet 416 between the needle 56 and cap 401 can be
accomplished by any means well known in the pertinent art.
The structural integrity of the components of arthroscope 400 is
enhanced by filling the space within the cap 401 with an epoxy
material. This is accomplished after the image guide 32 and fiber
bundle 122 have been properly positioned within the needle 56 and
have had their proximal ends respectively engaged for exposure
through the apertures 404 and 406 on base plate 402. Consequently,
the port 412, shown in FIG. 9A is provided for introducing an epoxy
material into the cap 401 after the other components have been
properly positioned.
As will be appreciated by the skilled artisan, it is important to
the operation of the arthroscope 400 that it be optically aligned
with camera assembly 202. Specifically, it must happen that image
guide 32 be aligned with focusing optic 116 of the camera assembly
202, and that the fiber bundle 122 be aligned with the fiber 130.
This, of course, is accomplished through the physical connection of
the arthroscope 400 to the camera assembly 202. The optical effect,
however, must be oriented with the physical apparatus so that the
operator will know where he is looking with the arthroscope 400.
For the arthroscope 400 this orientation is easily accomplished by
providing visual means on the cap 401 to indicate the relationship
between the image guide 32 and the orientation of the lens 48 at
the distal end of the image guide 32. Specifically, the clip 410 is
formed differently than the clip 408 so that the differences in
their appearance can be used for orienting the arthroscope 400
during its operation.
OPERATION
In the operation of arthroscope 10, reference is initially made to
FIGS. 1 and 2. Cannula assembly 68 with attached cannula 64 is
detached from scope assembly 80. A trocar (not shown) is positioned
through cannula 64, and the trocar is inserted into knee 14 to
establish the entry site 12 for cannula 64. Once cannula 64 has
been inserted into knee 14, the trocar can be removed from cannula
64. Disposable scope assembly 80 can then be attached to camera
assembly 100, and camera assembly 100 placed in light communication
with lamp 20. Also, camera assembly 100 is electrically connected
to CCU 24. The disposable scope assembly and attached camera
assembly 100 are inserted into cannula 64 to establish probe 30,
and cannula assembly 68 is engaged with scope assembly 80.
When probe 30 has been inserted into knee 14 as disclosed and
disposable scope assembly 80 has been attached to camera assembly
100, scope assembly 80 can be rotated clockwise and
counterclockwise relative to camera assembly 100 to selectively
focus the camera on the back of the image guide 32. More
particularly, in reference to FIGS. 7 and 8, when scope assembly 80
is rotated relative to camera assembly 100, image guide 30 is
rotated about its axis 44, as indicated by arrow 294. Recall that
front tube 96 (and, hence, image guide 30) can be rotated
.+-.170.degree. relative to axis 44, so that the angle represented
by arrow 294 in FIG. 8 is approximately 340.degree.. Thus, image
guide 30 can be rotated through 340.degree.. As image guide 30
rotates, distal base 54 of GRIN lens 48 moves through a
donut-shaped swath, and the viewing area 296 through which light
can pass to enter distal base 54 moves through a relatively large
region 298. Consequently, light from a relatively large region of
knee 14 can enter distal base 54 of GRIN lens 48, and the image of
this light processed by arthroscope 10 as described above for
display on CRT 26 and recording by VCR 28. After the examination of
patient 16, scope assembly 80 can be detached from camera assembly
100 and disposed of in a suitable receptacle, and a new scope
assembly (not shown) engaged with camera assembly 100 for
permitting the examination of another patient with arthroscope
10.
The operation of arthroscope 200 is in all essential respects
identical to the operation of arthroscope 10, with the exception
that cannula assembly 206 can rotate relative to scope assembly
204. Stated differently, scope assembly 204 can be rotated relative
to cannula assembly 206, i.e., cannula assembly 206 can remain
rotationally stationary with respect to the operator of arthroscope
200. By permitting cannula assembly 206 to remain stationary
relative to the operator of arthroscope 200, fluid line 230 also
remains stationary relative to the operator of arthroscope 200.
Consequently, fluid line 230 will not become wrapped around cannula
assembly 206 and will accordingly not unduly interfere with the
operation of arthroscope 200.
The arthroscope 400 is, in all important respects, similar to the
arthroscope 200. Like arthroscope 200, and arthroscope 10, the
componentry of arthroscope 400 is simplified and it is manufactured
with materials which permit disposal of the arthroscope 400 after
it has been used.
While the particular arthroscope as herein shown and disclosed in
detail is fully capable of obtaining the objects and providing the
advantages herein before stated, it is to be understood that it is
merely illustrative of the presently preferred embodiments of the
invention and that no limitations are intended to the details of
construction or design herein shown other than as described in the
appended claims.
* * * * *